Details of 2014 paper scripts

Model

Galactic scaling relations between the (surface densities of) the gas mass and the star formation rate are known to develop substantial scatter or even change form when considered below a certain spatial scale. In a recent paper (Kruijssen & Longmore 2014), we introduced an uncertainty principle for star formation that explains this breakdown on small scales with the incomplete statistical sampling of independent star-forming regions. The model can be used to predict and interpret the small-scale failure of galactic star formation relations. Crucially, the model predicts a scale-dependent bias of the gas depletion time-scale when centring an aperture on gas or stellar peaks, which is sensitive to (and hence provides a direct measure of) the physical size and time-scales involved in the star formation process, such as its duration or the molecular cloud lifetime. The uncertainty principle and its associated framework therefore provides a powerful tool to constrain these largely unknown quantities. A checklist detailing the required steps for its observational application can be found in Appendix A2 of the 2014 paper.

Thanks to its general form, the uncertainty principle can also be applied to other astrophysical systems. The fundamental point is that if a macroscopic correlation is caused by a time-evolution, then it must break down on small scales because the subsequent phases are resolved. This opens up a new avenue to measure the time-scales governing a broad range of astrophysical processes, such as the time-evolution of star-forming cores, protoplanetary discs, or galaxies and their nuclei. For a detailed derivation we refer the reader to the main paper, which can be accessed on ADS and arXiv through the links below.

https://ui.adsabs.harvard.edu/abs/2014MNRAS.439.3239K/abstract

http://arxiv.org/abs/1401.4459

Scripts

Fortran and IDL scripts were provided with the Kruijssen & Longmore (2014) paper, which are provided in the 2014/ folder of this repository.

The Fortran routines are provided in a module and therefore cannot be used as stand-alone tools. In order to function properly, the module and its functions need to be called from a program that they are used in. Example programs are provided in the 2014/KL14principle_F90/ folder. A more detailed explanation is available in the routine header.

The IDL routines can be used from the IDL command line as stand-alone tools, and can also be called from any desired program. As for the Fortran routines, a more detailed explanation is available in the routine header.